This invention relates to sphincterograms, and more particularly to a hydraulic sphincterogram device and a sphincterography method which is especially adapted for use in diagnosis of anal dysfunction, such as anal incontinence and rectal prolapse, the sphincterogram device also being adapted for use as an anal sphincter exerciser.
Anal incontinence (the inadvertant release of rectal contents due to failure of the anorectal/pelvic musculature) and rectal prolapse (the protrusion of the rectum through the anus) are common, embarrassing and, not surprisingly, under-diagnosed problems. It has been suggested that two distinct muscular mechanisms maintain fecal continence: (1) squeeze of the muscle fibers of the anal sphincter closes the anal canal lumen, and (2) contraction of the puborectalis--levator ani muscles flattens the distal rectum horizontally and kinks it at the anorectal angle thereby preventing transmission of intra-abdominal pressure into the anal canal. Anal incontinence may be associated with short anal canal length, low anal squeeze pressures and a wide (flat) anorectal angle. Rectal prolapse may be associated with a flat anorectal angle with or without low squeeze pressures.
Radiographic studies have been developed which allow actual visualization of the anal canal and measurement of the anorectal angle. These studies have heretofore been tedious, time consuming, unpleasant and messy. For example, S. Phillips and D. Edwards, Some Aspects of Anal Continence and Defaecation, 6 Gut 396-406 (1965), disclosed a method for determining the shape and position of the anal canal during defecation with cineradiography after coating the mucosa of the anal canal with barium sulfate powder. Barium soaked swabs, metal beaded chains, and various consistancies of barium have also been used to determine the anorectal angle.
The use of a balloon proctogram has been suggested as a tool for diagnosis of anal function. For example, Preston, Lennard-Jones and Thomas, The Balloon Proctogram, 71 Br. J. Surg. 29 (1984), discloses a barium filled balloon used to simulate a soft stool. After insertion and inflation of the balloon, a patient sits on a radiolucent lavatory seat. While the patient is sitting, the level of the pelvic floor, change of the anorectal angle and behavior of the anal sphincters during straining and defecation are visually demonstrated with lateral radiographs.
While the simplicity and cleanliness of this barium filled balloon is desirable, the particular design described above is disadvatageous in that it does not provide for measurement of anal canal (sphincter) pressure and fatigability of the anal musculature. The other methods outlined above, in addition to being unpleasant and messy, share this disadvantage. Therefore, one distinct muscular mechanism for maintaining anal continence has been ignored by these approaches to diagnosis of anal incontinence.
Also, these techniques do not provide for exercise of the anal sphincter, which may be a promising treatment for some forms of anal dysfunction, such as anal incontinence. "Anal aerobics", however, is not part of the traditional treatment of anal incontinence. An excercise for strengthening the anal musculature should include repeated relaxation and contraction of the anal sphincter. By definition, contraction must be against pressure that is below the maximum anal canal squeeze pressure and above the opening pressure of the resting anal sphincter. Any apparatus and method for exercising the anal musculature should be easy to use and designed to prevent excessive strain and internal injuries. Ideally, an apparatus and method for anal exercises should be capable of determining anal function, and an apparatus and method for determining anal function should be capable of exercising the anal musculature.